| Date | Fri, 15 Apr 2022 16:14:36 +0200 | Subject | Re: [RFC PATCH v5 072/104] KVM: TDX: handle vcpu migration over logical processor | From | Paolo Bonzini <> |
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On 3/4/22 20:49, isaku.yamahata@intel.com wrote: > From: Isaku Yamahata <isaku.yamahata@intel.com> > > For vcpu migration, in the case of VMX, VCMS is flushed on the source pcpu, > and load it on the target pcpu. There are corresponding TDX SEAMCALL APIs, > call them on vcpu migration. The logic is mostly same as VMX except the > TDX SEAMCALLs are used. > > Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> > --- > arch/x86/kvm/vmx/main.c | 20 +++++++++++++-- > arch/x86/kvm/vmx/tdx.c | 51 ++++++++++++++++++++++++++++++++++++++ > arch/x86/kvm/vmx/x86_ops.h | 2 ++ > 3 files changed, 71 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c > index f9d43f2de145..2cd5ba0e8788 100644 > --- a/arch/x86/kvm/vmx/main.c > +++ b/arch/x86/kvm/vmx/main.c > @@ -121,6 +121,14 @@ static fastpath_t vt_vcpu_run(struct kvm_vcpu *vcpu) > return vmx_vcpu_run(vcpu); > } > > +static void vt_vcpu_load(struct kvm_vcpu *vcpu, int cpu) > +{ > + if (is_td_vcpu(vcpu)) > + return tdx_vcpu_load(vcpu, cpu); > + > + return vmx_vcpu_load(vcpu, cpu); > +} > + > static void vt_flush_tlb_all(struct kvm_vcpu *vcpu) > { > if (is_td_vcpu(vcpu)) > @@ -162,6 +170,14 @@ static void vt_load_mmu_pgd(struct kvm_vcpu *vcpu, hpa_t root_hpa, > vmx_load_mmu_pgd(vcpu, root_hpa, pgd_level); > } > > +static void vt_sched_in(struct kvm_vcpu *vcpu, int cpu) > +{ > + if (is_td_vcpu(vcpu)) > + return; > + > + vmx_sched_in(vcpu, cpu); > +} > + > static int vt_mem_enc_op(struct kvm *kvm, void __user *argp) > { > if (!is_td(kvm)) > @@ -199,7 +215,7 @@ struct kvm_x86_ops vt_x86_ops __initdata = { > .vcpu_reset = vt_vcpu_reset, > > .prepare_guest_switch = vt_prepare_switch_to_guest, > - .vcpu_load = vmx_vcpu_load, > + .vcpu_load = vt_vcpu_load, > .vcpu_put = vt_vcpu_put, > > .update_exception_bitmap = vmx_update_exception_bitmap, > @@ -285,7 +301,7 @@ struct kvm_x86_ops vt_x86_ops __initdata = { > > .request_immediate_exit = vmx_request_immediate_exit, > > - .sched_in = vmx_sched_in, > + .sched_in = vt_sched_in, > > .cpu_dirty_log_size = PML_ENTITY_NUM, > .update_cpu_dirty_logging = vmx_update_cpu_dirty_logging, > diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c > index 37cf7d43435d..a6b1a8ce888d 100644 > --- a/arch/x86/kvm/vmx/tdx.c > +++ b/arch/x86/kvm/vmx/tdx.c > @@ -85,6 +85,18 @@ static inline bool is_td_finalized(struct kvm_tdx *kvm_tdx) > return kvm_tdx->finalized; > } > > +static inline void tdx_disassociate_vp(struct kvm_vcpu *vcpu) > +{ > + /* > + * Ensure tdx->cpu_list is updated is before setting vcpu->cpu to -1, > + * otherwise, a different CPU can see vcpu->cpu = -1 and add the vCPU > + * to its list before its deleted from this CPUs list. > + */ > + smp_wmb(); > + > + vcpu->cpu = -1; > +} > + > static void tdx_clear_page(unsigned long page) > { > const void *zero_page = (const void *) __va(page_to_phys(ZERO_PAGE(0))); > @@ -155,6 +167,39 @@ static void tdx_reclaim_td_page(struct tdx_td_page *page) > free_page(page->va); > } > > +static void tdx_flush_vp(void *arg) > +{ > + struct kvm_vcpu *vcpu = arg; > + u64 err; > + > + /* Task migration can race with CPU offlining. */ > + if (vcpu->cpu != raw_smp_processor_id()) > + return; > + > + /* > + * No need to do TDH_VP_FLUSH if the vCPU hasn't been initialized. The > + * list tracking still needs to be updated so that it's correct if/when > + * the vCPU does get initialized. > + */ > + if (is_td_vcpu_created(to_tdx(vcpu))) { > + err = tdh_vp_flush(to_tdx(vcpu)->tdvpr.pa); > + if (unlikely(err && err != TDX_VCPU_NOT_ASSOCIATED)) { > + if (WARN_ON_ONCE(err)) > + pr_tdx_error(TDH_VP_FLUSH, err, NULL); > + } > + } > + > + tdx_disassociate_vp(vcpu); > +} > + > +static void tdx_flush_vp_on_cpu(struct kvm_vcpu *vcpu) > +{ > + if (unlikely(vcpu->cpu == -1)) > + return; > + > + smp_call_function_single(vcpu->cpu, tdx_flush_vp, vcpu, 1); > +} > + > static int tdx_do_tdh_phymem_cache_wb(void *param) > { > u64 err = 0; > @@ -425,6 +470,12 @@ int tdx_vcpu_create(struct kvm_vcpu *vcpu) > return ret; > } > > +void tdx_vcpu_load(struct kvm_vcpu *vcpu, int cpu) > +{ > + if (vcpu->cpu != cpu) > + tdx_flush_vp_on_cpu(vcpu); > +} > + > void tdx_prepare_switch_to_guest(struct kvm_vcpu *vcpu) > { > struct vcpu_tdx *tdx = to_tdx(vcpu); > diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h > index 8b871c5f52cf..ceafd6e18f4e 100644 > --- a/arch/x86/kvm/vmx/x86_ops.h > +++ b/arch/x86/kvm/vmx/x86_ops.h > @@ -143,6 +143,7 @@ void tdx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event); > fastpath_t tdx_vcpu_run(struct kvm_vcpu *vcpu); > void tdx_prepare_switch_to_guest(struct kvm_vcpu *vcpu); > void tdx_vcpu_put(struct kvm_vcpu *vcpu); > +void tdx_vcpu_load(struct kvm_vcpu *vcpu, int cpu); > > int tdx_vm_ioctl(struct kvm *kvm, void __user *argp); > int tdx_vcpu_ioctl(struct kvm_vcpu *vcpu, void __user *argp); > @@ -166,6 +167,7 @@ static inline void tdx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) {} > static inline fastpath_t tdx_vcpu_run(struct kvm_vcpu *vcpu) { return EXIT_FASTPATH_NONE; } > static inline void tdx_prepare_switch_to_guest(struct kvm_vcpu *vcpu) {} > static inline void tdx_vcpu_put(struct kvm_vcpu *vcpu) {} > +static inline void tdx_vcpu_load(struct kvm_vcpu *vcpu, int cpu) {} > > static inline int tdx_vm_ioctl(struct kvm *kvm, void __user *argp) { return -EOPNOTSUPP; } > static inline int tdx_vcpu_ioctl(struct kvm_vcpu *vcpu, void __user *argp) { return -EOPNOTSUPP; }
This patch and the next one might even be squashed together.
Otherwise
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
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